This application claims the benefit of Korean Application No. 2001-54153, filed Sep. 4, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an apparatus for fine-adjusting an orientation of an optical device, and more particularly, to an apparatus capable of finely and easily adjusting an orientation of an optical device with respect to an imaging device.
2. Description of the Related Art
An apparatus including an optical device requires accurate orientation alignment of the optical device therein. When light emitted from a light source inaccurately radiates onto a position of the optical device, an optical efficiency of the optical advice is lowered, thereby degrading a performance of the apparatus including the optical device.
For example, in a three-panel projection system, an inaccurate orientation adjustment of xcex/4-wave plates disposed in front of red, green, blue imaging apparatuses causes inappropriate polarization or produces light beams of undesired wavelengths, thereby degrading the quality of an image projected onto a screen and adversely affecting a contrast ratio (hereinafter, referred to as a xe2x80x9ccontrastxe2x80x9d).
FIG. 1 is a perspective view of a conventional fine-adjusting apparatus adjusting an orientation of a xcex/4-wave plate 13 with respect to an imaging device 19. The fine-adjusting apparatus includes a xcex/4-wave plate base 15 into which the xcex/4-wave plate 13 is mounted, a base plate 17 positioned on imaging device 19, and a bracket 11 to which the xcex/4-wave plate 13 is coupled.
In assembling the conventional fine-adjusting apparatus, the base plate 17 is mounted to the imaging device 19, and the xcex/4-wave plate base 15 supporting the xcex/4-wave plate 13 is placed on the base plate 17. After the xcex/4-wave plate 13 is coupled to the bracket 11, the bracket 11 is fixed to the base plate 17 having screw apertures 10a, 10b, 10c, and 10d, and then to the imaging device 19 having screw apertures 20a, 20b, 20c, and 20d, by screws (not shown).
In the conventional fine-adjusting apparatus, the xcex/4-wave plate base 15 is rotated along a circle formed in the bracket 11 by inserting a sharply tipped tool into indentations 3 and 5 formed on the xcex/4-wave plate base 15 until the xcex/4-wave plate 13 is in an optimal position. Then, the xcex/4-wave plate 13 is fixed to a position of the bracket 11 to complete a fine adjustment. After the fine-adjustment is completed, the xcex/4-wave plate base 15 and the base plate 17 are bonded to each other using a bonding agent.
The conventional fine-adjusting apparatus requires an extra device for the fine-adjustment. Manually rotating the xcex/4-wave plate base 15 using the extra device in the conventional fine-adjusting apparatus described above may have a large variation and thus fails to accurately adjust the orientation of the xcex/4-wave plate base 15 with respect to the image device 19.
The conventional fine-adjusting apparatus uses the bracket 11 to fix the xcex/4-wave plate base 15 holding the xcex/4-wave plate 13. The structure of the bracket 11 tightens the xcex/4-wave plate 13 so that the stress is transferred to the xcex/4-wave plate 13, thereby deteriorating the uniformity of the image projected onto the screen. In addition, the conventional fine-adjusting apparatus has a problem of difficulty in fixing the xcex/4-wave plate 13 on the xcex/4-wave plate base 15 after the xcex/4-wave plate 13 is fine-adjusted with respect to the xcex/4-wave plate base 15.
When the conventional fine-adjusting apparatus having the above described structure is applied to adjust an orientation of an optical device, such as a xcex/4-wave plate, in a system, it is difficult to finely adjust the orientation and fix a position of the optical device to an image device, and thus an overall performance of the system degrades.
To solve the above and other problems, it is an object of the present invention to provide a precise orientation adjusting apparatus capable of easily and finely adjusting an orientation of an optical device and capable of easily fixing a position of the optical device.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects, there is provided an apparatus for finely adjusting an orientation of an optical device. The apparatus includes a base plate which supports the optical device and is rotatable to the left and right, a bracket coupled to the base plate such that the base plate is rotatable with respect to the bracket, a spring disposed between the base plate and the bracket to apply an elastic force to the base plate, and an adjusting element pushing the base plate against the bracket to adjust a relative position of the optical device with respect to the bracket.
According to an aspect of the present invention, the base plate has coupling slots at upper and lower ends, and one of the coupling slots horizontally extends to allow the base plate to rotate with respect to the bracket. According to another aspect of the present invention, the bracket has coupling pins at upper and lower ends, and one of the coupling pins acts as a rotation axis of the base plate while the coupling pins engage the respective coupling slots. The base plate has on one side a screw aperture to be engaged with the adjusting element. The bracket includes a support projection supporting the spring. The adjusting element may be a screw.